Magnesium (Mg) composites exhibit exceptional properties, making them ideal for diverse applications in the medical, aerospace, and energy industries. The extensive use of Mg-based composites has driven ongoing efforts to enhance their properties and performance. Therefore, the present work focused on the fabrication of Mg-Zn-Mn surface composites reinforced with Zinc oxide (ZnO) through friction stir processing (FSP). The effect of the addition of ZnO on microstructure, mechanical properties, corrosion, and wear behavior was investigated. The development of the microstructure is analyzed using a scanning electron microscope (SEM) and X-ray diffraction analysis. Surface topography and roughness are analyzed using atomic force microscopy (AFM) and revealed a Ra value of 68.4 nm. The mechanical properties of the friction stir processed samples are investigated using Vickers microhardness equipment. The FSP/ZnO-Mg-Zn-Mn surface nanocomposites demonstrated a microhardness of 152.7 Hv, which is 2.4 times greater than that of the H-Mg-Zn-Mn base materials. The enhancement in the corrosion resistance of the FSP/ZnO-Mg-Zn-Mn surface nanocomposites is primarily due to the combined effect of the refined grains and the uniform dispersion of ZnO particles. Furthermore, this surface composite had the best wear resistance as a result of significant grain refinement and higher hardness.

This study investigates the mechanical properties of Al6061-TiB2-fly ash reinforced monolithic and hybrid composites, fabricated using the stir casting technique. The experiment involved the preparation of both monolithic composites by varying TiB2 (3-6 wt%) and hybrid composites by varying TiB2 (1-3 wt%) and fly ash (3-5 wt%) within the Al6061 matrix. Preheated reinforcement particles were introduced to the matrix alloy under controlled stirring conditions to ensure proper dispersion. Mechanical testing was conducted on the fabricated composites to evaluate their hardness and tensile strength. The results indicate that the hybrid composites exhibit superior mechanical properties compared to the base Al6061 alloy and the monolithic composites. The hardness of the hybrid composites A1T3F (Al6061 + 1%TiB2 + 3% fly ash) and A3T5F (Al6061 + 3%TiB2 + 5% fly ash) were significantly improved, reaching 134 HV and 146 HV, respectively, compared to 74 HV for the base alloy. The tensile strength of the hybrid composites also exceeded that of the monolithic composites, demonstrating the synergistic reinforcement effect of TiB2 and fly ash. However, attempts to incorporate higher levels of reinforcement (TiB2 5% and fly ash 7%) were unsuccessful due to agglomeration issues. The results indicate that the hybrid composites provide a cost-effective solution with enhanced mechanical properties, making them a more economical and efficient alternative to monolithic composites reinforced solely with TiB2.

The aim of this work is to investigate the variations in microstructure, hardness, wear and surface roughness between as-cast and heat treated trace elements added A356 alloy. Alloy A was prepared by adding 1 wt.% magnesium to A356 alloy which was used as the base material for the preparation of alloys with zinc (Zn) and copper (Cu) particles as alloying elements. Other set of samples was fabricated where Cu-coated Zn and Cu were added as reinforcements to base matrix A. The microstructural analysis indicated that the addition of Zn to A356 as an alloying element had a limited effect on controlling the grain size during solidification compared to Cu. The addition of Cu as reinforcement resulted in a higher proportion of pro eutectic α-Al phase, leading to finer grain boundaries. Micro-polishing test was conducted on the alloys and composites by determining the surface roughness (Ra) value using profilometer to study the changes in surface roughness under individual load conditions of 20 and 40 N. In the as-cast condition, the addition of Cu increased the hardness by 39% and 58% over the base alloy, respectively. Age-hardening treatment significantly enhanced the wear resistance properties of unreinforced alloys and composites at both aging temperatures, especially at 100 °C. Composite samples exhibited excellent surface finish (lower surface roughness) compared to alloy samples, attributed to the presence of hard reinforcement particles.

Austempered ductile iron is an innovative material obtained by subjecting it to an austempering heat treatment. The wide application of this material is because its properties are comparable to those of steel, which has a much lower weight. However, the machinability of this material is always a difficult task owing to its high hardness. This problem becomes more complex when a considerable amount of Mn is added. In this study, a novel two-step austempering heat treatment was performed on spheroidal graphite iron containing different amounts of manganese. Although the novel heat treatment method helps to obtain a superior combination of hardness and impact, its effect on machinability must be determined. This study provides the results of machinability tests carried out on austempered ductile iron with various manganese contents produced using the novel method. Scanning electron microscope images of the microstructures revealed a typical ausferrite structure with no segregation of manganese at the grain boundary. This is evident from the good tool life obtained in the machinability tests. Regression equations are fitted to determine the tool life and surface roughness for machining parameters with a range of values considered in this study. The results obtained have shown that till 1 wt% of manganese alloyed austempered ductile iron can be successfully produced using the novel heat treatment method. This helps to obtain the optimum combination of strength and impact properties.

This study investigates the mechanical and microstructural properties of aluminum matrix composites (AMCs) reinforced with cobalt-coated carbon nanotubes (CNTs) and Al2024 powder, tailored for aircraft and automotive applications. Using Al7075 alloy as the matrix, composites were fabricated via stir casting, incorporating varying proportions of cobalt-coated CNTs and Al2024 powder. The electroless cobalt coating, applied at thicknesses of 4, 6, 8, and 10 mu m, facilitated the uniform distribution and enhanced the compatibility of reinforcements with the Al7075 matrix. Four distinct samples were developed: pure Al7075 alloy, Al7075 with 2 wt.% CNTs, Al7075 with 2 wt.% Al2024 powder, and a hybrid composite combining 2 wt.% of each reinforcement. Microstructural analysis revealed that the 10 mu m coating thickness was critical for maintaining reinforcement integrity during the melt phase, preventing crack formation and reinforcement agglomeration. Mechanical testing through vickers hardness and phase analysis using X-ray diffraction analysis, demonstrated that the hybrid composite (A3) exhibited superior hardness and reduced natural aging tendencies compared to its counterparts. Peak aging at 120 degrees C resulted in the formation of intermetallic compounds like CuAl2 and MgZn2, contributing to improved mechanical properties. These findings highlight the significance of optimizing coating thickness and aging conditions to enhance the performance of AMCs, making them suitable for high-performance applications in the aerospace and automotive industries.

Among the various types of recently released composite materials, particle-reinforced metal matrix composites (MMCs), in particular aluminum as the matrix material, have been shown to provide substantial industrial benefits in the automotive and aerospace sectors. The current research focused on the corrosion behavior of an Al7075 hybrid composite in 0.1 M hydrochloric acid (HCl) and 3.5% NaCl media at different temperatures. Electrochemical techniques, such as Tafel polarization (TP) and electrochemical impedance spectroscopy (EIS), were employed to study the corrosion behavior in the respective solutions. The results showed that the corrosion rate of the studied specimen increased from 31.77 to 47.61 mmy−1 in 0.1 M HCl and from 0.26 to 1.28 mmy−1 in 3.5% NaCl with increasing temperature. The corrosion current density of the Al7075 hybrid composite in 0.1 M HCl is on the order of 10−3 Acm2, and that in 3.5% NaCl is on the order of 10−5 Acm2. This confirms the increased rate of composite corrosion in the 0.1 M HCl medium compared to that in the 3.5% NaCl medium. A suitable mechanism was proposed for the corrosion of the Al7075 hybrid composite in both media.

The present study reflects on the wear behaviour characteristics of A356 composite with trace addition of copper and copper-coated zinc as reinforcements. Dry sliding wear tests were conducted on fabricated as-cast and heat treated composites by varying load of 20-60 N under constant sliding speed of 1 m/s and sliding distance of 3000 m. Results confirmed that copper-coated zinc was successfully introduced as reinforcement into A356 matrix using two-step casting method. Scanning Electron Microscope (SEM) images confirmed the presence and homogeneous distribution of the added reinforcements in the matrix. T6 treatment with addition of Cu reinforcement facilitated age hardening showing 121% hardness improvement compared to as-cast matrix A356. At lower loads, wear results showed 117-134% enhanced wear resistance in composite reinforced with 1 wt.% Cu and aging at 100°C. However at higher loads, 153-210% improvement in wear resistance was observed. Overall, copper and Cu-coated zinc reinforced composite along with T6 treatment exhibited significant improvement in hardness wear property compared to as-cast matrix A356 alloy.

This research work highlights the prediction of hardness behaviour of age-hardened LM4 and its composites fabricated using a two-stage stir casting method with TiB2 and Si3N4. MATLAB - Artificial Neural Networks is used to predict the age-hardening behaviour of LM4 and its composites. Experiments (hardness and tensile tests) are conducted to collect data for training an ANN model as well as to investigate the effect of reinforcements and age-hardening treatment on LM4 and its composites. The results show that with an increment in the reinforcement wt.%, there is an enhancement in hardness and ultimate tensile strength (UTS) values within the monolithic composites. As-cast hybrid composites display a 37 to 54% improvement in hardness compared to as-cast LM4. Heat-treated samples, specifically those treated with peak aging with MSHT and 100°C aging, perform better than as-cast samples and other heat-treated samples in terms of UTS and hardness. Compared to as-cast LM4, MSHT, and 100°C aged samples display an 85 to 202% increment in VHN. Hybrid composites perform better in terms of hardness, while composites with 3 wt.% of TiB2 (L3TB) perform better in terms of UTS, peak aged (MSHT and 100°C aging) L3TB display 68% increment in UTS when compared to as-cast LM4. ANN model is developed and trained with five inputs (wt.% of TiB2, wt.% of Si3N4, type of solutionizing, aging temperature, and aging time) and one output (VHN) using different algorithms and a different number of hidden neurons to predict the age hardening behaviour of composites. Among them, Lavenberg-Marquardt (LM) training algorithm with normalized data and 30 hidden neurons performs well and shows a least average error of 1.588364. The confirmation test confirms that the trained ANN model can predict the output with an average %error of 0.14 using unseen data.

This technical paper demonstrates the possibilities of nickel (Ni) coated Al2024 powder reinforcement in an Al7075 matrix using the liquid stir casting technique. Additionally, the paper focuses on achieving stable properties by implementing artificial aging heat treatment. To apply the Ni coating, the electroless nickel plating technique was utilized, and a minimum coating thickness of 8 μ m was determined to effectively prevent the dissolution of Al2024 powder reinforcements within the Al7075 matrix. Stir casting facilitated the uniform dispersion of the coated Al2024 powder up to a weight percentage of 7%. Subsequently, the Al7075 alloy and composites underwent artificial aging through solution heat treatment (SHT) at 450 °C for 4 h, followed by water quenching and aging at temperatures of 120, 150, and 180 °C. Aging at 120 °C was found to yield superior results compared to aging at 150 and 180 °C, thus identified as the optimum aging temperature. When the Ni coating thickness was increased beyond the optimal 8 μ m, the resulting enhancements in hardness for both as-cast and peak-aged specimens, as well as the tensile strength, were not significant. The improvements observed were only marginal, ranging between 2 to 3%. Fracture surface analysis revealed that the predominant fracture mode in the Al7075 alloy was ductile, characterized by dimple rupture. In the as-cast Al7075-(7%, 8 μ m) Al2024 composite, a mixed fracture mode comprising both brittle and ductile characteristics was observed. In the peak-aged (120 °C) Al7075-(7%, 8 μ m)Al2024 composite, the overall fracture mode exhibited a dominant brittle nature. Analytical techniques including XRD, TEM, and EDS confirmed the presence of Mg _2 Si, MgZn _2 , CuAl _2 , and CuAl _2 Mg phases in the peak-aged (120 °C) Al7075-(7%, 8 μ m) Al2024 composite. These phases contributed to the enhancement of the properties of both the Al7075 alloy and its composites. The developed composites can be used in automobile parts and aerospace applications.

The effect of heat treatment and various reinforcement additions on aluminium alloys is discussed in this article. Metal matrix composites are now widely employed in aerospace and automotive applications. Composites utilization has been rapidly increasing because of their notable properties, viz. improved strength and impact resistance. The current review work, on the other hand, collects the possibility of using different reinforcements in bare with or without hybridization. Data assessment with property analysis will pave the path for future hybridization research endeavours. The purpose of this article is to collect data on aluminium matrix composites with TiB2, WC, ZrB2 and B4C reinforcements and provide collective information regarding prospective improvements that might be made based on the data.

This technical paper presents the successful reinforcement of nickel (Ni) coated duralumin powder in an Al7075 matrix using the liquid stir casting technique and property stability obtained by heat treatment. Ni coating is performed by electroless nickel plating technique where 8 pm coating thickness was observed to be the minimum required to prevent dissolution of the reinforcements (duralumin powder) in the matrix (Al7075). During stir casting it was observed to uniformly disperse the coated duralumin powder up to 7 wt.%. Al7075 alloy and composites were artificially aged with solution heat treatment (SHT) performed at 450 & DEG;C for 4 h, water quenched and then aged at 120, 150 and 180 & DEG;C. Al7075 alloy and composites were naturally aged for 24 weeks in atmospheric temperature after peak aging. Composites aged at 120 & DEG;C exhibited superior results and considered as optimum aging temperature compared to those aged at 150 and 180 & DEG;C. Peak hardness values in 7075-7Dp+8T composite improved by 108% and 7075-7Dp+10T composite improved by 110% when compared to peak aged (at 120 & DEG;C) Al7075 alloy. Moreover, composites with coated reinforcement displayed a higher resistance to natural aging, with reductions of 53.5 and 54.4% in natural aging tendency compared to the naturally aged Al7075 alloy for 7075-7Dp+8T and 7075-7Dp+10T composites respectively. However, an increase in Ni coating thickness beyond the optimal 8 pm did not significantly improve as cast and peak hardness or natural aging resistance. XRD analysis confirmed that there is presence of CuAl2, CuAl2Mg, Mg2Si, and MgZn2 phases in peak-aged (120 & DEG;C) 7075-7Dp+8T sample. Considering the limited impact on property enhancement and the financial burden associated with thicker coatings, a coating thickness of 8 pm is recommended as compared to 10 pm.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The magnetic and electrical characteristics of Ni-Mn quinary Heusler alloys are studied in the current work. The results concern the materials’ magnetic and electrical behavior. The physical property measurement system (PPMS) and superconducting quantum interference device (SQUID) were used at various magnetization levels to determine the results. The addition of Fe helps to form the alloy into a smart memory alloy with magnetocrystalline anisotropy, twin border mobility, and varied magnetic and martensite transition temperature characteristics. Character changes in the superparamagnetic (SPM) and paramagnetic (PM) alloys occur between 26 and 34 °C. The curves are supported by the alloy’s martensitic transition temperature change. A large refrigeration capacity is identified in the alloy. These properties are an indication of the alloys’ application prospects. Entropy change helps to detect the inverse magnetocaloric effect in the alloy, whereas adiabatic temperature change helps identify the origin and validity of reverse magnetic properties. The transition temperature changes occur when austenite’s sigma is larger than that of martensite, and as the magnetic field increases, the temperature declines. Isothermal magnetization curves, a large (MR)/B value at low and high magnetic fields, and temperatures near the transformation point suggest that small-crystal Heusler alloys have tremendous promise for low and high magnetic field magnetoresistance applications.

In the present work, it is experimented to reinforce duralumin powder (3 to 7 wt %.)into Al7075 matrix by stir casting technique. Since matrix and reinforcement both have almost similar melting temperatures,theleast expensive additive manufacturing metallurgical route seems to be the best fit. In this study, an effort was made to produce the Al7075 matrix composite reinforced with duralumin by a novel stir casting method by coating duralumin powders with nickel which has high temperature melting point compared to reinforcement material. Nickel has goodwettability and avoids undesirable chemical reactions between the reinforcement and matrix at higher temperatures, acting as a protector for both the duralumin and matrix. Since, aging kinetics of duralumin (Al2024) and Al7075 are different, both positively respond to heat treatment in a single stretch for propertyalteration. During stir casting, even though duralumin melts along with the matrix, it will be under the solid protection barrier (coat) of nickel, avoiding dissolution with the Al7075 matrix.To verify the presence of reinforcement duralumin in the matrix and to decide the soundness of the casting produced by stir casting, confirmation tests are made like microstructures with EDS and micro hardness distribution. The microstructure analysis of the compositeshowedan even distribution of nickel coated duralumin in the matrix when the coating thickness of a nickel is greater than 8 µm. The hardness test analysis has shown an improvement in the hardness with the increase in the weight % of the reinforcement. Improvement in the hardness of composites is due to an increase in dislocation number, which shows higher resistance to plastic deformation [2].Statistical analysis has shown that the coating of reinforcement does not have any significant effect on the mechanical properties. The regression equation is fit to determine the hardness of the composite involving the factors within the range of values considered for this study.

Nowadays, metal matrix composites are being comprehensively used in aero and automotive applications. The usage of composites increased because of their impressive properties viz., improved strength, impact resistance, and tailored features. Compared to uncoated, coated reinforcements in the matrix improves wettability with thinner grain boundary, grain fineness, and the ability for secondary hardening. Improvement in thermal expansion and conductivity makes the composite suitable for moderate temperature shock resistance is the new openings in the field. Conventional liquid stir casting, Rheo-process, and Diffusion roll bonding are some of the methods employed for the processing of composites. Hybridisation of reinforcements with at least one as coated in the matrix improves solid solution strengthening of composites, hence responsible for improved strength and bulk hardness. Generally, a critical literature survey points to copper and nickel coatings. Copper coating rises microhardness, shows poor EMI shielding effectiveness compared to nickel-coated, whereas, nickel-coated reinforcement composites show excellent corrosion resistance compared to that of copper-coated reinforcement. Cobalt-coated nanoparticles reinforced composites upsurges compressive strength and tribological properties compared to nickel-coated ones. However, the extensive review work undertaken collects the possibilities of using different reinforcements in bare state and coated state with or without hybridisation. A comparison of data with property analysis will open the way for further research activities with hybridisation of both or single-coated reinforcements in the matrix and may help to prepare the standard guidelines to advance with a statistical approach. The objective of the present work is to collect the data on the aluminium matrix composites with different reinforcements in coated as well as bare forms and dig on the possibilities for property enhancement.